Circle-drafting instrument.



WITNESSES:

0. L. NICHOLS & R. HOGAN.

PATENTED APR. 14, 1908,

CIRCLE DRAFTING INSTRUMENT.

APPLICATION FILED AUG. 29, 1907.

2 SHEETS-SHEET 1.

rm: NORRIS PETER5 CO. \YA

INVENTORS.

harles L.Nic11o1s A BY Raleigh Hogan.

A TTORN E Y.

PATENTED APR. 14, 1908. G. L. NICHOLS & R. HOGAN.

CIRCLE DRAFTING INSTRUMENT.

APPLICATION FILED AUG. 29, 1907.

2 SHEETS-SHEET 2.

a 20 p in WITNESSES: INVENTORS GA/m Charles L Nichols a 777 772 W ByRaleigh Hogan.

ATTORNEY.

m: rmmus pz-rsns :0, WASHINGTON, n. L:

PATENT @FFTCE.

CHARLES L. NICHOLS AND RALEIGH HOGAN, OF FRANKLIN, INDIANA.

CIRCLE-DRAFTIN G INSTRUMENT.

Specification of Letters Patent.

Patented April 14, 1908.

Application filed August 29, 1907. Serial No. 390,621.

To all whom it may concern:

Be it known that we, CHARLES L. NIoHoLs and RALEIGH HOGAN, both ofFranklin, county of Johnson, and State of Indiana, have invented acertain new and useful Circle-Drafting Instrument; and we do herebydeclare that the following is a full, clear, and exact descriptionthereof, reference being had to the accompanying drawings, in which likeletters refer to like parts.

Our invention relates to improvements in drawing instruments adapted toform curves that may represent the arcs of circles of dimensions toogreat to be made conveniently by ordinary instruments.

This invention is peculiarly adapted for making drawings for patternswhere arcs of large circles are to be drawn. For that purpose theinstrument is longitudinally adj ustable so that such arcs may be drawnwithout making any measurements or calculations with reference to thecenter of the are. This renders the instrument very valuable in draftingsheet metal patterns, cutting glass, making railroad curves and thelike.

The nature of the invention will be understood from the accompanyingdrawings and the following description and claims.

In the drawings Figure 1 is a side elevation of the device with a partcentrally broken away. Fig. 2 is a plan view of the device. Fig. 3 is acentral longitudinal section of the device with the ends broken away.Fig. 4 is a rear view of the device. Figs. 5 and 6 are diagrams showingthe manner of using the device.

Referring now to the details of the construc tion of the device hereinshown for the purpose of illustrating our invention, there is alongitudinally extending rod 10 on the forward end of which a bracket 11is secured that has a portion 12 projecting beyond the forward end ofthe rod horizontally and provided with a central vertically disposedhole in which a caster-frame 13 extends so as to turn for adjustment.This caster-frame has a shoulder for supporting the projection 12 of thebracket 11 and the upper part of said caster-frame is a threaded rodadapted to receive the washer 15 and the knurled nut 16 which clampsdown upon the projection 12 of the bracket 11 and thus clamps thecasterframe rigidly in any desired position. The lower end of thecaster-frame is vertically slotted at 17 and in said slot thecaster-wheel 18 is mounted, said wheel being a disk with a sharpenedperiphery so that it will travel very accurately over drawing paper andshould be mounted so as to have as little play as possible in order tocontribute to accuracy in the operation of the instrument. A still wireor finger 19 is secured in said caster-frame and projects forwardly andis used for indicating the direction of the front wheel and measuringangles.

The rearward end of the main rod 10 is supported by the following means:The rear axle 20 has the wheels 21 mounted upon its ends. These wheelsare mounted as accurately as possible so that they will have little playand yet move freely. Their peripheries should also be rather sharp sothey will travel accurately over drawing aper without slipping. On saidaxle a tubu ar bearing 22 is mounted. The ends of said bearing are splitand externally threaded and upon the same the knurled nuts 23 aresecured for clamping the bearing on the axle. A sleeve 24 is integralwith and transversely secured upon bearing 22 and at an absolute rightangle therewith for the purpose of receiving the main rod 10 so that thewhole rear carriage may be slipped longitudinally of said rod. One endof said sleeve is split and threaded for the knurled nut 25 whereby thesleeve may be clamped in any desired position upon said rod. By thismeans the rear support for said rod can be adjusted longitudinallythereof so as to increase or diminish the distance between the frontwheel and the pencil 26 which extends downward from the tubular bearing22 and is held in the pencil holder 27.

A quadrant 30 is mounted on the caster frame 13 so as to rotate saidcaster frame and adjust the angle of the front wheel 18 with referenceto the main rod 10. Said quadrant is actuated by the worm 31 mounted inthe bearing 32 that extends transversely of the main rod and is clampedthereto by the set screw 33. This enables said bearing to be adjusted onsaid rod 10. The worm is actuated by a finger wheel 34 and the worm ismoved up so as to mesh with the toothed periphery of the quadrant andactuate said quadrant. The outer edge of the quadrant moves in and isguided by a horizontal slot in the worm bearing 32 and upon saidquadrant there is a scale 36 to indicate the angle at which the frontwheel 18 is or may be set. For accurately and finely adjusting thequadrant the finger wheel 34 has a minute scale. The disk 134 on bearing32 beside the wheel 34 has an indicating mark on it and the arrangementis such that one revolution of the wheel 34 will move the quadrant onedegree. This permits minute adjustment of the quadrant.

In operation when it is desired to trace the arc of a large circle andthe degree of curvature of that are is known the device is set byturning the worm and quadrant so as to bring the desired degree mark onthe quadrant over the center of the main rod 10 and then the front nut16 is clamped so as to hold the front wheel at the angle to which it isadjusted. Then the device as a whole is moved over the drawing paper andthe pencil thereon will trace the desired curve or arc, however greatthe circle might be if completed.

For making drawings for patterns, sheet metal work and the like, thisinvention is peculiarly well adapted and can be used for that purposewithout the need of any calcula- For illustration, if one desires todraw tions. approximately the frustum of a hollow cone 01 certaindimensions, such as shown in Fig. 6,

there is usually given the dimensions of the two circumferences AB andOD and the length of the cone M N. These are drawn in straight lines asindicated and the problem is to draw the proper are for the top and bottom of the cone so that when the sheet of metal is rolled into conicalshape, the two ends will be in parallel planes. After the lines AB, CDand MN are drawn, with the line MN bisecting said lines AB and CD, thecorresponding ends of the lines AB and OD are connected to form the sidelines AC and BD, or at least one of them, say BD. Then the line G-E isdrawn so as to bi-sect lines B-M and N-D. Then the line BEL is drawnfrom the point D at right angles to BD. Then line EF is drawn from thepoint at a right angle to the line G-E. Then the pointer or pencil ofthe machine is placed on the point E and the front wheel is turned to anangle that will cause the pointer 19 to parallel the line EF so as togive the front wheel the desired angularity to describe the arc AB. Byclamping the front wheel in the position thus indicated and moving theinstrument over the drawing pa er the pencil or marker will indicate thearc -B. In the same way the arc C-D is drawn. Or suppose the patterndesired is for a breast, as shown in Fig. 5. There the diameters of thevessel to be constructed are given, AB, CD and also the height M-N.These lines are drawn as in Fig. 6, above described and the arcs AB andCD are determined in the same manner as the arcs described in Fig. 6,ex-

l/Vhat We claim as our invention and desire to secure by Letters Patentis:

1. A drawing instrument including a rod, a wheel mounted caster-like forsupporting one end of said rod, means for clamping it at any desiredangle with reference to the rod, a pair of wheels and means carried bysaid pair of wheels for supporting the other end of the rod, thedistance between said front and rear Wheels being adjustablelongitudinally of the rod; substantially as and for the purpose setforth.

2. A drawing instrument including a rod, a bracket secured to one end ofsaid rod and caster-frame mounted vertically in said bracket, a wheelmounted in the lower end of said frame, means for clamping saidcasterframe in said bracket so as to hold the said wheel at any desiredangle with relation to the rod, wheels for supporting the rear end ofsaid rod, an axle on which said wheels are mounted, a sleeve-likebearing in which said axle is mounted that is long1tudinally slidable onsaid rod with one end thereof threaded and split, and a nut for clampingsaid sleeve in any desired position on said rod.

3. A drawing instrument including a rod, a bracket secured to one end ofsaid rod and caster-frame mounted vertically in said bracket, a wheelmounted in the lower end of said frame, means for clamping saidcasterframe in said bracket so as to hold the said wheel at any desiredangle with relation to the rod, wheels for supporting the rear end ofsaid rod, an axle on which said wheels are mounted, a sleeve-likebearing in which said axle is mounted that is longitudinally slidable onsaid rod with one end thereof threaded and split, a nut for clampingsaid sleeve in any desired position on said rod, and a lead pencilholder extending down centrally from the bearing for said axle.

4. A drawin instrument including a rod, a pair of whee ls for supportingone end of said rod, a single wheel mounted caster-like on the other endof said rod for supporting the same, said wheels being adjustable onsaid rod with relation to each other a scale marked. segment foradjusting the angle of said single wheel with relation to said rod,means for clamping said single wheel in position when adjusted, andmeans mounted on said rod for engaging the periphery of said segment andactuating the same.

5. A drawing instrument including a rod, a pair of wheels for supportingone end of said rod, a single wheel mounted caster-like on the other endof said rod for supporting the same, a scale marked segment foradjusting the an tion to said rod, means for clamping said single wheelin position when adjusted, means mounted on said rod for engaging theperiphery of said segment and actuating the same, and a fingerprojecting forward from the 'le of said single wheel with relameans inwhich said front wheel is mounted that indicates the angle at which saidwheel is set.

6. A drawing instrument including a rod, a bracket secured on one endthereof, a caster frame mounted vertically in said bracket, a wheel onthe lower end of said frame, a segment mounted on said casterframe thatis horizontally disposed and has a toothed periphery that is providedwith a scale, means for clamping said caster bracket in position to holdsaid wheel at any desired angle with relation to said rod, a pair ofrear wheels, means slidably mounted on said rod on which said rearwheels are mounted, means for clamping the same in any desired positionon said rod, a frame mounted on said rod with a horizontal slot in it inposition for the periphery of said segment to fit and move in said slot,a worm mounted in said frame transversely of said rod that engages thetoothed periphery of said segment for actuating the same, and means foroperating said worm, substantially as set forth.

In witness whereof, we have hereunto af- 25 fixed our signatures in thepresence of the witnesses herein named.

CHARLES L. NIOHOLSQ j RALEIGH HOGAN.

lVitnesses: V. H. LOCKWOOD,

OLIVE BREEDEN.

